<?php
/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

/**
 * Preconditions for handlers.
 */
class HandlerPreconditions {

  private function __construct() {}

  public static function requireNotEmpty($item, $message) {
    if (empty($item)) {
      throw new InvalidArgumentException($message);
    }
  }

  public static function requireEmpty($item, $message) {
    if (! empty($item)) {
      throw new InvalidArgumentException($message);
    }
  }

  public static function requireSingular($item, $message) {
    self::requireNotEmpty($item, $message);
    if (count($item) != 1) {
      throw new InvalidArgumentException($message);
    }
  }

  public static function requirePlural($item, $message) {
    self::requireNotEmpty($item, $message);
    if (count($item) <= 1) {
      throw new InvalidArgumentException($message);
    }
  }

  public static function requireCondition($cond, $message) {
    if (! $cond) {
      throw new InvalidArgumentException($message);
    }
  }
}
